Method of making a valve member for internal combustion engines



ER FOR ES Dec. 19, 1967 G. KUBERA METHOD OF MAK N EMB GIN A VALVE M INTERNAL BUSTION EN 2 Sheets-Sheet 1 Filed Jan. 18, 1965 INVENTOR.

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Fl G ll 37 J 35 FIGJS KUBERA G. F MAKI METHOD 0 NG A VALVE MEMBER FOR INTERNAL COMBUSTION ENGINES Filed Jan. 18, 1963 United States Patent 3,358,350 METHOD OF MAKING A VALVE MEMBER FOR INTERNAL COMBUSTION ENGINES Gerhard Kubera, Barsinghausen, Germany, assignor to T eves-Thompson & C0. G.m.b.H., Frankfurt am Main, Germany, a corporation of Germany Filed Jan. 18, 1963, Ser. No. 252,497 Claims priority, application Germany, Jan. 26, 1962, K 45,772 12 Claims. (Cl. 29156.7)

ABSTRACT OF THE DISCLOSURE Method of making a valve member for the intake and exhaust valve of an internal combustion engine whereby a solid billet of cylindrical configuration receives an extrudable mandrel extending into it from one end and is extruded to form a narrow stem while the unperforated other extremity is forged by axial pressure to produce a head extending transversely to the stern. A copper insert of greater deformability than the mandrel is inserted ahead of it into the blind bore of the stem and may remain therein or be removed upon withdrawal of the mandrel. Withdrawal of the mandrel leaves a blind bore which is filled with metallic sodium.

My present invention relates to a valve member for internal-combustion engines and a method of making same.

It is known to provide valve members for internal-combustion engines, especially for the intake and exhaust ports of the cylinders thereof, which comprise an elongated stem and a valve plate secured to the stem. Generally, this valve stem is formed independently of the valve plate and secured to the latter by welding. When both valve stem and valve plate are entirely of steel construction, they are characterized by relatively low heat conductivity so that overheating of the valve member, and, consequently, dislocation thereof results during operation. Moreover, the welded junction between valve stem and plate is subjected to extremely high stresses in operation at high rates (e.g., in aircraft engines).

It is an object of the present invention to provide an improved valve member for internal-combustion engines which is capable of withstanding the substantial internal stresses present therein and yet is of simple construction and of inexpensive manufacture.

It is another object of the present invention to provide a valve member of this character which is capable of dissipating thermal energy at a relatively high rate.

Still another object of this invention is to provide a method of making such a valve member.

These objects are attained, in accordance with the invention, by providing a valve member which comprises an elongated, generally cylindrical stem and a valve plate integral therewith at one extremity of the stem. The integral nature of the valve plate, which extends generally transversely to the stem, and the latter substantially prevents any stresses from effecting a rupture of the member at the junction between stem and plate. It has been found that it is possible to increase the heat-dissipating character of this valve member when, in addition to making the stem and plate integral, the stem is provided with an axially extending bore terminating substantially at the plate. This bore can be filled with a material having a higher thermal conductivity than that of the stern, which advantageously is composed of steel or a refractory metal. This material of higher thermal conductivity may be metallic sodium and is encased in the bore of the hollow stem by closing its mouth. In addition, the transversely extending plate may be provided with a cavity communicating with the bore of the stem and containing a material of higher conductivity than that of the metal constituting the valve stem. This material may either be identical with that filling the bore or different as desired. According to one embodiment of the invention, the material filling the cavity can be copper while that contained within the bore is metallic sodium in intimate contact with the copper so that no substantial resistance to heat flow is observable at the interface. Since, in all cases, the valve plate is integral with the stem, there is little danger that, under the stresses of operation, the plate and stem will separate from one another and damage other parts of the engine.

According to another aspect of the invention, a valve member of the aforedescribed type is formed by axially inserting an extrudable mandrel partly into a generally cylindrical billet at one extremity thereof. The billet and the mandrel are then extruded to form at least part of the stem, whereupon removal of the mandrel produces a blind bore in the stem terminating inwardly of the other end of the billet. This other end of the billet is, consequently, unperforated so that the valve plate can be forged at this end of the billet integrally with the stem.

The bore formed upon withdrawal of the mandrel can then be filled with the material whose thermal conductivity is higher than that of the body whereupon the mouth of this bore can be closed (e.g., by plug welding, deposit welding or by deforming the stem in the region of the mouth). When the extrusion process is effected by applying an axial pressure to the unperfor-ated other end of the billet, this portion of the latter has the diameter of the original billet prior to extrusion so that radial deformation to produce the transversely extending plate can be carried out with case. To prevent any enlargement of the mandrel at the blind end of the bore, which might render it impossible to withdraw the mandrel from the billet, the mandrel or core can be formed with a conical convergence in the direction of the other end prior to insertion thereof into the billet. The mandrel or core can thus be received within a blind axial hole formed in the billet or forced into the latter. In the former case, it is possible to insert a block of material more plastically deformable than the mandrel in the hole prior to or together with insertion of the mandrel. When axial pressure is applied to the billet to extrude it through the die, the block is deformed generally radially to produce a cavity within the body substantially at the transverse plate. The block can thus be removed by melting, if it has a lower melting point than that of the body, or can remain within the latter. When the block remains within the body, it is preferred to constitute it of a material having a higher thermal conductivity than that of the valve plate and stem. This block may thus be composed of copper while the billet and the mandrel can be composed of steel, a material of high thermal conductivity such as metallic sodium being intro duced into the bore after Withdrawal of the mandrel.

It is also possible to carry out the extrusion process by applying an axial pressure to the perforated end of the billet. In this case the nonperforated end of the latter can nevertheless be deformed radially to produce the plate. It should be noted, however, that the stem, in the region of the mouth of the bore, will have a diameter equal substantially to that of the original billet and, of course, greater than that of the remainder of the stem. The added material in this region may, however, be utilized to close the bore by a forging operation so that the stem is substantially of uniform external diameter.

The above and other objects, features and advantages of the present invention will become more readily appar ent from the following description, reference being made to the accompanying drawing in which:

FIG. 1 is an axial cross-sectional view through a billet and the apparatus for extruding same at an initial stage of the method;

FIGS. 2-4 are similar views showing further operative stages;

FIGS. 4A and 4B are cross-sectional views taken respectively along the lines IVA-IVA and IVBIVB of FIG. 4;

FIGS. 5-8 are axial cross-sectional views through valvemember bodies during successive stages in the course of a modified method;

FIG. 8A is a fragmentary axial cross-sectional view showing the mouth of the bore of a valve member;

FIGS. 9-12 are axial cross-sectional views through a valve-member body showing successive method steps according to still another embodiment of the invention;

FIG. 12A is a view similar to FIG. 8A illustrating a variation;

FIGS. 13-16 are axial cross-sectional views diagrammatically illustrating successive stages of still another method according to the invention; and

FIG. 16A is a fragmentary axial cross-sectional view showing a modified valve-plate-and stem arrangement.

In FIGS. 1-4, 4A and 43, I show a billet 1, of generally cylindrical con-figuration, whose internal blind hole receives the core of mandrel 2. The extrusion means for forming the stem of the valve member comprises a die holder 40 whose die 40' is provided with an aperture 41. The extrusion press is diagrammatically represented by a hydraulic cylinder 44 whose piston 43 bears upon a ring 42 which, in turn, rests against the perforated end of the billet '1 and receives the extremity of mandrel 2 projecting therefrom. When the hydraulic cylinder 44 is energized to shift the piston 43 in the direction of arrow 45 the billet .1 and mandrel 2 are extruded in the direction of arrow 46 through the die aperture 41 to produce an elongated cylindrical stem 43. This stem terminates in an unperforated other end 4 and has an enlarged head 5 whose diameter is approximately equal to that of the billet 1 prior to extrusion.

As can be seen from FIGS. 2 and 3, the valve plate 7 is formed in the other end 4 of the extruded body by forging (e.g., with the aid of successively applied axially displaceable forging dies 47, 50 which are reciprocable in the direction of arrow 48 by the usual mechanism, not shown). Die 50 flares the unperforated extremity 4 generally radially and forms it against a counterdie 49. A holder 51, through which the projecting extremity 6 of core 2 passes, holds the head 5 in place while the mandrel is withdrawn in the direction of arrow 52. The resulting lined bore 54' can then be filled with a material 54 (e.g., metallic sodium) having a higher thermal conductivity than that of the body 3, 7. The mouth of the bore is then closed by exerting a radial pressure (arrows 53) on the enlarged head 5 to force the material constituting this head into the bore and forge it closed at its mouth 8. This forging operation is effected so that the entire stem 3 is of substantially uniform cross-section.

In the method illustrated diagrammatically in FIGS. 5-8, the mandrel or core 13 is formed with a conical convergence 11 in the direction of the unperforated end a of the billet 10 whose perforated extremity is provided with a conically diverging recess 12 which communicates with the hollow interior of the billet. When an axial pressure is exerted by the extrusion press 56 against the unperforated end of the billet 10 to force this billet through the die 55, the mandrel 13 is initially extruded to produce a core 15 surrounded by a sheath 14 of billet material. The resulting elongated stem 14 terminated in a head 16, at the unperforated end of the body, which has substantially the same diameter as that of the billet prior to extrusion. The head 16, against which the extrusion force was exerted, is then deformed radially with the aid of a forging die 58 which shapes an annular recess 18 into the outer face of the transverse valve plate 19 thus formed. This radial deformation also produces an axial stub 17 while preventing enlargement of the core 15 in such manner as to prevent its withdrawal. This stub can be removed by axial forging subsequently to the removal of the mandrel or by grinding, e.g., with the aid of a Wheel 59, with the mandrel present. The blind internal bore 14' formed in the stem 14 of the steel mandrel can then be filled with a material having a higher thermal conductivity (e.g., metallic sodium) as seen at 60 in FIG. 8A, whereupon the mouth 61 of this bore can be closed by a plug 62 which is held in place by a weldment 63.

An apparatus similar to that employed in connection with the method described With reference to FIGS. 5-8 can also be used to extrude the billet 20 and the extrudable mandrel 23. The blind hole 21 preformed in the billet 29 is, unlike the conieally terminating hole of billet 10, of uniform circular cross-section throughout its length except for the region of its mouth at which it diverges outwardly. Thus a block 24 of a material, such as copper, more plastically deformable than the steel mandrel and, advantageously, having a higher thermal conductivity than that of the billet, can be inserted into the hole 21 prior to or together with the insertion of the mandrel 23 which is provided with a tapering extremity 22 in the manner previously described. Application of extruding pressure to the unperforated end 20 in generally axial direction, eiiects extrusion of the mandrel 23 and the billet 20 at its perforated end 20" through the die which, although not shown in FIGS. 9-12, is generally similar to those previously described. The resulting core 26 is thus surrounded by an elongated generally cylindrical sheath 25 and has an extremity 27 projecting axially therefrom. The axial extrusion pressure results in a substantially radial deformation of the block 24 (FIG. 10) without any substantial similar deformation of the tapered mandrel 23 so that the latter can be withdrawn (FIG. 11) in the direction of arrow 64 to produce a blind bore 65 in the stem 25 (FIG. 12). Prior to withdrawal of the mandrel, however, the head 28 of the body, which is not passe-d through the die and thus has a diameter substantially equal to that of the billet 20, can be shaped with the aid of forging dies 66 and 67 (FIG. 11) to produce the valve plate 29 with its annular recess. There is no need, in this instance, to insure the production of a stub, such as that illustrated at 17, since axial forging pressure will only result in further radial deformation of the relaitvely soft block 24. When the latter has a melting point below of the body, it can be removed in a liquid state with heating to yield a cavity in the transverse plate 29 which communicates with the bore 65 and can be filled with the material of high thermal conductivity introduced into the latter. Since the block 24 is itself composed of a material having high conductivity, it can remain in the body, whereupon metallic sodium 68 may be poured into the bore and into thermal contact therewith (FIG. 12). The mouth of the bore can then be closed by deposition welding at 70 (FIG. 12A).

The method steps illustrated in FIGS. 13-15 are generally similar to those previously described with the exception that the mandrel 32 is of cylindrical configuration without conical convergence while the block 31 is a cylindrical slug coextensive with the internal portion of the blind hole 21 formed in the billet and axially aligned with the mandrel 32. Upon extrusion, the frustoconical slug 35 is radially deformed in the head 36 of the body while the hollow stem 33 thereof surrounds the core 34 (FIG. 14). The head 36 can then be forged into a valve plate 37 integral with the stem 33 (FIG. 15) whereupon removal of the core 34 produces a bore 34' which is filled with metallic sodium 34" in intimate contact with the deformed slug 35. The latter is, of course, composed of copper or another material having a higher thermal conductivity than that of the steel body. This slug can, however, be removed (FIG. 16A) to produce a cavity 35' aligned with the bore 34 which, like the latter, is filled with metallic sodium. In either case, the mouth of the bore can be closed as previously mentioned.

The invention described as illustrated is believed to admit of many modifications, e.g., the use of a bipartite mandrel having a portion of greater plastic deformability and higher thermal conductivity with the method described with reference to FIGS. 14, within the ability of persons skilled in the art, all such modifications being deemed included Within the spirit and scope of the appended claims.

I claim:

1. A method of making a valve member for an internal-Combustion engine, comprising the steps of forming a body having a hollow elongated, generally cylindrical narrow stem and a relatively wide valve head extending transversely to said stem and unitarily integral therewith at one end of said stem by axially inserting an extrudable mandrel only partly into a generally cylindrical billet at one extremity thereof whereby said mandrel terminates Within said billet short of its other extremity, extruding said billet and said mandrel to form said stem, thereafter axially forging said head from said other extremity beyond said mandrel in the direction of insertion thereof, and removing said mandrel subsequently to extrusion to produce a blind bore in said stem While leaving said other extremity of said billet unperforated.

2. The method defined in claim 1, further comprising the steps of filling said bore with and thereafter closing the mouth of said bore formed upon withdrawal of said mandrel.

3. The method defined in claim 1 wherein said billet is extruded by applying an axial pressure to said other extremity, thereby forcing said one extremity through a die.

4. The method defined in claim 3 wherein the end of said mandrel proximal to said other extremity is formed with a conical convergence in the direction of said other end prior to insertion of said mandrel into said billet.

5. A method of making a valve member for an internal combustion engine, comprising the steps of:

(a) forming a generally cylindrical billet with a blind axially extending bore opening at one extremity of said billet and terminating short of the other extremity thereof; 7

(b) inserting into said hole a block of a relatively plastically deformable material;

(c) inserting into said hole behind said block an extrudable mandrel of lesser plastic deformability than said block;

(cl) extruding said billet and said mandrel to form an elongated generally cylindrical stem;

(e) forging said other extremity of said billet by applying axial pressure thereto with a valve head extending transversely to said stem and unitarily integral therewith While leaving said other extremity of said billet unperforated deforming said block generally radially; and

(f) removing said mandrel subsequently to extrusion in step (d) to produce a bore in said stem.

6. The method defined in claim 5 wherein said block is composed of a material having a higher thermal conductivity than that of said body and remains in said bore after removal of said mandrel.

7. The method defined in claim 5 wherein said block is removed from said billet after removal of said mandrel to produce a cavity in said plate communicating with said bore.

8. The method defined in claim 7 wherein said block is composed of a material having a lower melting point than that of said block and is removed by melting.

9. The method defined in claim 5 wherein said block is composed of copper.

10. The method defined in claim 1 wherein said billet is extruded by applying an axial pressure to said one extremity, thereby extruding said other extremity through a die, and wherein the forging of said head in said other extremity of said billet is effected subsequent to its extrusion.

11. The method defined in claim 10 wherein said one extremity has a diameter larger than that of the remainder of said stern upon removal of said mandrel, further comprising the step of deforming said one extremity of said billet to close the mouth of said bore while shaping it to conform in diameter to said remainder of said stem.

12. The method defined in claim 1 wherein said blind bore is closed at its mouth by welding.

References Cited UNITED STATES PATENTS 2,452,636 11/ 1948 Cummingham et a1. 2,093,772 9/1937 Colwell. 2,070,589 2/ 1937 Giacchino. 1,984,728 12/ 1934 Colwell. 2,407,561 9/ 1946 Lincoln 123-188 2,881,750 4/1959 Hanink 123188 2,513,939 7/1950 Hoern 29156.7 3,040,417 6/ 1962 Newton 29-156.7

FOREIGN PATENTS 1,076,078 10/1954 France. 1,027,488 4/ 1958 Germany. 624,412 7/1961 Canada.

CHARLIE T. MOON, Primary Examiner.

FRED E. ENGETEHALER, RICHARD WILKINSON,

Examiners.

J. L, CLINE, A. L. SMITH, Assistant Examiners. 

5. A METHOD OF MAKING A VALVE MEMBER FOR AN INTERNAL COMBUSTION ENGINE, COMPRISING THE STEPS OF: (A) FORMING A GENERALLY CYLINDRICAL BILLET WITH A BLIND AXIALLY EXTENDING BORE OPENING AT ONE EXTREMITY OF SAID BILLET AND TERMINATING SHORT OF THE OTHER EXTREMITY THEREOF; (B) INSERTING INTO SAID HOLE A BLOCK OF A RELATIVELY PLASTICALLY DEFORMABLE MATERIAL; (C) INSERTING INTO SAID HOLE BEHIND SAID BLOCK AN EXTRUDABLE MANDREL OF LESSER PLASTIC DEFORMABILITY THAN SAID BLOCK; (D) EXTRUDING SAID BILLET AND SAID MANDREL TO FORM AN ELONGATED GENERALLY CYLINDRICAL STEM; (E) FORGING SAID OTHER EXTREMITY OF SAID BILLET BY APPLYING AXIAL PRESSURE THERETO WITH A VALVE HEAD EXTENDING TRANSVERSELY TO SAID STEM AND UNITARILY INGEGRAL THEREWITH WHILE LEAVING SAID OTHER EXTREMITY OF SAID BILLET UNPERFORATED DEFORMING SAID BLOCK GENERALLY RADIALLY; AND (F) REMOVING SAID MANDREL SUBSEQUENTLY TO EXTRUSION IN STEP (D) TO PRODUCE A BORE IN SAID STEM. 